Vertical fin field effect transistor devices with a replacement metal gate

ABSTRACT

A method of forming a fin field effect transistor complementary metal oxide semiconductor (CMOS) device is provided. The method includes forming a plurality of multilayer fin templates and vertical fins on a substrate, wherein one multilayer fin template is on each of the plurality of vertical fins. The method further includes forming a dummy gate layer on the substrate, the plurality of vertical fins, and the multilayer fin templates, and removing a portion of the dummy gate layer from the substrate from between adjacent pairs of the vertical fins. The method further includes forming a fill layer between adjacent pairs of the vertical fins. The method further includes removing a portion of the dummy gate layer from between the fill layer and the vertical fins, and forming a sidewall spacer layer on the fill layer and between the fill layer and the vertical fins.

BACKGROUND Technical Field

The present invention generally relates to vertical fin field effecttransistor (FinFET) devices, and more particularly to FinFETs withreplacement metal gates.

Description of the Related Art

A Field Effect Transistor (FET) typically has a source, a channel, and adrain, where current flows from the source to the drain, and a gate thatcontrols the flow of current through the device channel. Field EffectTransistors (FETs) can have a variety of different structures, forexample, FETs have been fabricated with the source, channel, and drainformed in the substrate material itself, where the current flowshorizontally (i.e., in the plane of the substrate), and FinFETs havebeen formed with the channel extending outward from the substrate, butwhere the current also flows horizontally from a source to a drain. Thechannel for the FinFET can be an upright slab of thin rectangularsilicon (Si), commonly referred to as the fin with a gate on the fin, ascompared to a MOSFET with a single gate parallel with the plane of thesubstrate. Depending on the doping of the source and drain, an n-FET ora p-FET can be formed. Two FETs also can be coupled to form acomplementary metal oxide semiconductor (CMOS) device, where a p-channelMOSFET and n-channel MOSFET are electrically coupled together.

SUMMARY

In accordance with an embodiment of the present invention, a method offorming a fin field effect transistor complementary metal oxidesemiconductor (CMOS) device is provided. The method includes forming aplurality of multilayer fin templates and vertical fins on a substrate,wherein one multilayer fin template is on each of the plurality ofvertical fins. The method further includes forming a dummy gate layer onthe substrate, the plurality of vertical fins, and the multilayer fintemplates. The method further includes removing a portion of the dummygate layer from the substrate from between adjacent pairs of thevertical fins. The method further includes forming a fill layer betweenadjacent pairs of the vertical fins. The method further includesremoving a portion of the dummy gate layer from between the fill layerand the vertical fins, and forming a sidewall spacer layer on the filllayer and between the fill layer and the vertical fins.

In accordance with another embodiment of the present invention, a methodof forming a fin field effect transistor complementary metal oxidesemiconductor (CMOS) device is provided. The method includes forming abottom source/drain layer on a substrate. The method further includesforming a plurality of multilayer fin templates and vertical fins on thebottom source/drain layer, wherein one multilayer fin template is oneach of the plurality of vertical fins. The method further includesforming a bottom spacer layer on the bottom source/drain layer and theplurality of vertical fins. The method further includes forming a gatedielectric layer on the plurality of vertical fins and the bottom spacerlayer, and forming a dummy gate layer on the gate dielectric layer, andthe multilayer fin templates. The method further includes removing aportion of the dummy gate layer from the gate dielectric layer frombetween adjacent pairs of the vertical fins, and forming a fill layer onthe gate dielectric layer between adjacent pairs of the vertical fins.The method further includes removing a portion of the dummy gate layerfrom between the fill layer and the vertical fins, and forming asidewall spacer layer on the fill layer and between the fill layer andthe vertical fins.

In accordance with another embodiment of the present invention, a finfield effect transistor complementary metal oxide semiconductor (CMOS)device is provided. The device includes a bottom source/drain layer on asubstrate. The device further includes a plurality of vertical fins in afirst subset and a plurality of vertical fins in a second subset on thebottom source/drain layer. The device further includes a gate dielectriclayer on each of the plurality of vertical fins in the first subset andthe plurality of vertical fins in the second subset. The device furtherincludes a work function layer on the gate dielectric layer on theplurality of vertical fins in the second subset, and a replacement workfunction material on the gate dielectric layer on the plurality ofvertical fins in the first subset. The device further includes asidewall spacer on the replacement work function material and gatedielectric layer.

These and other features and advantages will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description will provide details of preferred embodimentswith reference to the following figures wherein:

FIG. 1 is a cross-sectional side view showing a bottom source/drainlayer on a substrate, a fin layer on the bottom source/drain layer, afin template liner on the fin layer, a first fin template layer on thefin liner, and a second fin template layer on the first fin templatelayer, in accordance with an embodiment of the present invention;

FIG. 2 is a cross-sectional side view showing a plurality of verticalfins formed from the fin layer, and a multilayer fin template formedfrom the fin template liner, first fin template layer, and second fintemplate layer on each of the vertical fins, in accordance with anembodiment of the present invention;

FIG. 3 is a cross-sectional side view showing a bottom spacer layerformed on the bottom source/drain layer and plurality of vertical fins,in accordance with an embodiment of the present invention;

FIG. 4 is a cross-sectional side view showing a gate dielectric layerformed on the bottom spacer layer, walls of the plurality of verticalfins and multilayer fin template, a first work function layer formed onthe gate dielectric layer, and a dummy gate layer formed on the firstwork function layer, in accordance with an embodiment of the presentinvention;

FIG. 5 is a cross-sectional side view showing a heat treatment of thevertical fins, multilayer fin templates, gate dielectric layer, bottomspacer layer, first work function layer formed, and dummy gate layer, inaccordance with an embodiment of the present invention;

FIG. 6 is a cross-sectional side view showing a portion of the dummygate layer and work function layer removed from a surfaces of the gatedielectric layer, in accordance with an embodiment of the presentinvention;

FIG. 7 is a cross-sectional side view showing a fill layer formed in thespaces between the dummy gate layers on adjacent vertical fins, inaccordance with an embodiment of the present invention;

FIG. 8 is a cross-sectional side view showing a portion of the filllayer and gate dielectric layer removed to expose the underlying secondfin template slab, and the second fin template slab removed to exposethe first fin template slab, in accordance with an embodiment of thepresent invention;

FIG. 9 is a cross-sectional side view showing a portion of the dummygate layer removed to expose the sidewalls of the work function layer,and the first fin template slab removed to expose the underlying finliner plate, in accordance with an embodiment of the present invention;

FIG. 10 is a cross-sectional side view showing a portion of the workfunction layer and gate dielectric layer removed to expose the sidewallsof the vertical fins and fin liner plate, in accordance with anembodiment of the present invention;

FIG. 11 is a cross-sectional side view showing a sidewall spacer layerformed on the exposed surfaces of the fill layer, dummy gate layer, workfunction layer, gate dielectric layer, vertical fins, and fin linerplates, in accordance with an embodiment of the present invention;

FIG. 12 is a cross-sectional side view showing a masking layer formed ona portion of the sidewall spacer layer, and an exposed portion of thesidewall spacer layer removed from the fill layer to form sidewallspacers between the vertical fins and fill layer, and the exposed finliner plates removed from the top surfaces of the vertical fins, inaccordance with an embodiment of the present invention;

FIG. 13 is a cross-sectional side view showing a top source/drain formedwithin the sidewall spacers on the exposed top surfaces of the verticalfins, in accordance with an embodiment of the present invention;

FIG. 14 is a cross-sectional side view showing a protective layer formedon the sidewall spacer layer after removing a masking layer, and on theexposed surfaces of the fill layer, sidewall spacers, and topsource/drains, in accordance with an embodiment of the presentinvention;

FIG. 15 is a cross-sectional side view showing a second masking layerformed on a portion of the protective layer, in accordance with anembodiment of the present invention;

FIG. 16 is a cross-sectional side view showing a top source/drain formedwithin the sidewall spacers on the exposed top surfaces of the verticalfins after forming sidewall spacers, in accordance with an embodiment ofthe present invention;

FIG. 17 is a cross-sectional side view showing the second masking layerand protective layer removed, and source/drain caps formed on the topsource/drains, in accordance with an embodiment of the presentinvention;

FIG. 18 is a cross-sectional side view showing the dummy gate layer andwork function layer removed from around a subset of vertical fins, inaccordance with an embodiment of the present invention;

FIG. 19 is a cross-sectional side view showing a replacement workfunction material formed in the spaces formed by removing the dummy gatelayer from around the subset of vertical fins, in accordance with anembodiment of the present invention; and

FIG. 20 is a cross-sectional side view showing a conductive gate fillformed in the spaces formed by removing the dummy gate layer from arounda second subset of vertical fins, and source/drain and gate contactsformed in an interlayer dielectric (ILD) layer, in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention provide an approach to fabricatingvertical transport fin field effect transistor (VT FinFET) devices withreplacement metal gates that provides for forming n-type VT FinFETs andp-type VTFinFETs adjacent to each other on a substrate. A shared gatecomplementary metal oxide semiconductor (CMOS) device can be formed withreplacement metal gates. A conformal Si can be used to form a dummygate, and a late gate replacement can be used to form an active gatehaving the same gate length dummy gate.

Embodiments of the present invention provide a vertical transport finfield effect transistor (VT FinFET) devices with replacement metal gateswith an active gate having the same gate length dummy gate. An amorphoussilicon can be conformally deposited as a dummy gate layer thatdetermines the gate size of a subsequently formed active gate. Differentwork function layers and conductive gate fills can be used to formn-type VT FinFETs and p-type VTFinFETs adjacent to each other on thesubstrate. A shared gate complementary metal oxide semiconductor (CMOS)device can be formed with the replacement metal gates.

Exemplary applications/uses to which the present invention can beapplied include, but are not limited to: transistor device based memorycells (e.g., static random access memory (SRAM), dynamic random accessmemory (DRAM), latches, etc.), and transistor based logic cells (e.g.,NAND gates, NOR gates, XOR gates, flip-flops, etc.).

It is to be understood that aspects of the present invention will bedescribed in terms of a given illustrative architecture; however, otherarchitectures, structures, substrate materials and process features andsteps can be varied within the scope of aspects of the presentinvention.

Referring now to the drawings in which like numerals represent the sameor similar elements and initially to FIG. 1, a cross-sectional side viewof a bottom source/drain layer on a substrate, a fin layer on the bottomsource/drain layer, a fin template liner on the fin layer, a first fintemplate layer on the fin liner, and a second fin template layer on thefirst fin template layer is shown, in accordance with an embodiment ofthe present invention.

In one or more embodiments, a substrate 110 can be, for example, asingle crystal semiconductor material wafer or asemiconductor-on-insulator stacked wafer. The substrate 110 can includea support layer that provides structural support, and an activesemiconductor layer that can form devices. An insulating layer (e.g., aburied oxide (BOX) layer) may be between the active semiconductor layerand the support layer to form a semiconductor-on-insulator substrate(SeOI) (e.g., a silicon-on-insulator substrate (SOI)).

In one or more embodiments, the substrate 110 or an active semiconductorlayer can be a crystalline semiconductor, for example, a IV or IV-IVsemiconductor (e.g., silicon (Si), silicon carbide (SiC),silicon-germanium (SiGe), germanium (Ge)) or a III-V semiconductor(e.g., gallium-arsenide (GaAs), indium-phosphide (InP),indium-antimonide (InSb)). In various embodiments, the substrate 110 canbe a single crystal wafer.

In one or more embodiments, a bottom source/drain layer 120 can beformed on a substrate 110, where the bottom source/drain layer 120 canbe formed by implantation and/or an epitaxial or heteroepitaxial growthprocess, for example, molecular beam epitaxy (MBE), liquid phase epitaxy(LPE), or gas phase epitaxy (GPE). The bottom source/drain layer 120 canbe doped to be an n-type bottom source/drain layer or a p-type bottomsource/drain layer, where the dopant(s) can be introduced in situ (i.e.,during formation of a layer) or ex situ (i.e., after formation of alayer). In various embodiments, n-type dopants can be, for example,phosphorus (P) or arsenic (As), and p-type dopants can be, for example,boron (B) or gallium (Ga). In various embodiments, the bottomsource/drain layer 120 can be a semiconductor material, including, butnot limited to n-type (e.g., P or As) doped silicon (Si) or p-type(e.g., B) doped silicon-germanium (SiGe). The bottom source/drain layer120 can be the same semiconductor material as the substrate 110 ordifferent.

In various embodiments, the bottom source/drain layer 120 can have athickness in a range of about 10 nm to about 40 nm, or about 20 nm toabout 30 nm, although other thicknesses are also contemplated.

In one or more embodiments, a fin layer 130 can be formed on the bottomsource/drain layer 120 and substrate 110, where the fin layer can beformed by an epitaxial or heteroepitaxial growth process. The fin layer130 can have the same crystal orientation as the substrate 110 andbottom source/drain layer 120.

In various embodiments, the fin layer 130 can be a semiconductormaterial, where the fin layer 130 can be the same semiconductor materialas the substrate 110 and/or the bottom source/drain layer 120, or thefin layer 130 can be a different semiconductor material than thesubstrate 110 and/or the bottom source/drain layer 120. Use of adifferent semiconductor material for the fin layer 130 can be used toimpart a stress in the fin layer.

In one or more embodiments, a fin template liner 140 can be formed onthe fin layer 130, where the fin template liner 140 can be asemiconductor oxide formed by a thermal oxidation reaction of theexposed surface of the fin layer 130 or by a conformal deposition, forexample, atomic layer deposition (ALD), plasma enhanced ALD (PEALD), orlow pressure CVD (LPCVD). In various embodiments, the fin template liner140 can be silicon oxide (SiO).

In various embodiments, a first fin template layer 150 can be formed onthe fin template liner 140, where the first fin template layer 150 canbe formed by a conformal or blanket deposition, for example, chemicalvapor deposition (CVD) or plasma enhanced CVD (PECVD) to a predeterminedthickness, or etched back to an intended thickness, e.g., using anisotropic etch.

In various embodiments, the first fin template layer 150 can be ahardmask material, including, but not limited to, silicon nitride (SiN),silicon oxynitride (SiON), silicon carbonitride (SiCN), siliconboronitride (SiBN), silicon borocarbide (SiBC), silicon borocarbonitride (SiBCN), or combinations thereof, where the first fintemplate layer 150 can be a hardmask material different from the fintemplate liner 140 to provide etch selectivity.

In various embodiments, a second fin template layer 160 can be formed onthe first fin template layer 150, where the second fin template layer160 can be formed by a conformal or blanket deposition, for example,chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD) to apredetermined thickness, or etched back to an intended thickness, e.g.,using an isotropic etch.

In various embodiments, the second fin template layer 160 can be ahardmask material, including, but not limited to, silicon nitride (SiN),silicon oxynitride (SiON), silicon carbonitride (SiCN), siliconboronitride (SiBN), silicon borocarbide (SiBC), silicon borocarbonitride (SiBCN), or combinations thereof, where the second fintemplate layer 160 can be a hardmask material different from the fintemplate liner 140 and first fin template layer 150 to provide etchselectivity.

FIG. 2 is a cross-sectional side view showing a plurality of verticalfins formed from the fin layer, and a multilayer fin template formedfrom the fin template liner, first fin template layer, and second fintemplate layer on each of the vertical fins, in accordance with anembodiment of the present invention.

In one or more embodiments, one or more vertical fins 131 with amultilayer fin template can be formed on the bottom source/drain layer120 and substrate 110. The vertical fins 131 and fin templates can beformed by a multiple patterning fabrication process, for example, asidewall image transfer (SIT) process, a self-aligned double patterning(SADP) process, self-aligned triple patterning (SATP) process, or aself-aligned quadruple patterning (SAQP). The vertical fins 131 may beformed by a direct write process or double patterning process using, forexample, immersion lithography, extreme ultraviolet lithography, orx-ray lithography. The multilayer fin templates including a second fintemplate slab 161, a first fin template slab 151, and a fin liner plate141 can be formed from the second fin template layer 160, first fintemplate layer 150, and fin template liner 140 previously formed on thefin layer 130, as part of the patterning process. A sequence ofselective, directional etches, for example, a reactive ion etch (RIE),can be used to form the vertical fins 131 and multilayer fin templates.

In various embodiments, the widths of the semiconductor vertical fin(s)131 can be in a range of about 5 nanometers (nm) to about 15 nm, orabout 6 nm to about 10 nm, or about 6 nm to about 8 nm, although otherwidths are also contemplated.

In various embodiments, the height of the semiconductor vertical fin(s)131 can be in a range of about 20 nanometers (nm) to about 100 nm, orabout 30 nm to about 50 nm, although other heights are alsocontemplated. Although the vertical fins 131 are depicted in the figuresperpendicular to the substrate 110 (i.e., having a 90 degree angle), thefins can have a tapered sidewall that does not meet the substrate at aright angle (i.e., not exactly 90 degree). The top surface of thevertical fins 131 may not be perfectly flat or rectangular, but may havea convex curved surface. The substrate surface can have a curved(recessed) profile between the vertical fins 131. In variousembodiments, the bottom source/drain layer 120 can be formed afterformation of the vertical fin(s) 130, where the bottom source/drainlayer can be formed by dopant implantation.

FIG. 3 is a cross-sectional side view showing a bottom spacer layerformed on the bottom source/drain layer and plurality of vertical fins,in accordance with an embodiment of the present invention.

In one or more embodiments, an isolation region 170 can be formedthrough the bottom source/drain layer 120 to electrically separate thebottom source/drain layer into different segments below the verticalfins 131. The isolation region(s) 170 can be formed by etching a trenchthrough the bottom source/drain layer 120 and into the substrate 110,and filling the trench with a dielectric material, for example, siliconoxide (SiO). The isolation region(s) 170 can be formed between adjacentpairs of vertical fins 131.

In one or more embodiments, a bottom spacer layer 180 can be formed onthe bottom source/drain layer 120 and isolation regions 170, where thebottom spacer layer 180 can be formed by a directional deposition to apredetermined thickness, for example, by a high density plasma (HDP) orgas cluster ion beam (GCIB), or by a blanket deposition, for example,chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD) andetched back to an intended thickness, e.g., using an isotropic etch.

In various embodiments, the bottom spacer layer 180 can have a thicknessin a range of about 3 nm to about 10 nm, or about 5 nm to about 7 nm,although other thicknesses are also contemplated. The bottom spacerlayer 180 can cover a lower portion of the vertical fins 131 up to thethickness of the bottom spacer layer.

In various embodiments, the bottom spacer layer 180 can be a dielectricmaterial, including, but not limited to, silicon oxide (SiO), siliconnitride (SiN), silicon oxynitride (SiON), silicon carbonitride (SiCN),silicon boronitride (SiBN), silicon borocarbide (SiBC), silicon borocarbonitride (SiBCN), or combinations thereof. The bottom spacer layer180 can be a material different from the fin template slabs and plate toallow selective removal.

FIG. 4 is a cross-sectional side view showing a gate dielectric layerformed on the bottom spacer layer, walls of the plurality of verticalfins and multilayer fin template, a first work function layer formed onthe gate dielectric layer, and a dummy gate layer formed on the firstwork function layer, in accordance with an embodiment of the presentinvention.

In one or more embodiments, a gate dielectric layer 190 can be formed onthe bottom spacer layer 180 and the plurality of vertical fins 131 andmultilayer fin templates, where the gate dielectric layer 190 can beformed by a conformal deposition, for example, atomic layer deposition(ALD), plasma enhanced ALD (PEALD), or low pressure CVD (LPCVD). Thegate dielectric layer 190 can cover exposed surfaces of the bottomspacer layer 180, vertical fins 131, and multilayer fin templates.

In various embodiments, the gate dielectric layer 190 can be adielectric material, including, but not limited to, silicon oxide (SiO),silicon nitride (SiN), silicon oxynitride (SiON), silicon boronitride(SiBN), silicon boro carbonitride (SiBCN), silicon carbonitride (SiCN),silicon oxycarbonitride (SiOCN), a high-k dielectric, and combinationsthereof. Examples of high-k materials include but are not limited tometal oxides, such as, hafnium oxide (HfO), hafnium silicon oxide(HfSiO), hafnium silicon oxynitride (HfSiON), lanthanum oxide (LaO),lanthanum aluminum oxide (LaAlO), zirconium oxide (ZrO), zirconiumsilicon oxide (ZrSiO), zirconium silicon oxynitride (ZrSiON), tantalumoxide (TaO), titanium oxide (TiO), barium strontium titanium oxide(BaSrTiO), barium titanium oxide (BaTiO), strontium titanium oxide(SrTiO), yttrium oxide (YO), aluminum oxide (AlO), lead scandiumtantalum oxide (PbScTaO), and lead zinc niobate (PbZnNbO). The high-kmaterial may further include dopants such as lanthanum, aluminum,magnesium, or combinations thereof.

In various embodiments, the gate dielectric layer 190 can have athickness in a range of about 1 nm to about 3 nm, or about 2 nm,although other thicknesses are also contemplated.

In one or more embodiments, a work function layer 200 can be formed onthe gate dielectric layer 190, where the work function layer 200 can beformed by a conformal deposition.

In various embodiments, the work function layer 200 can be a conductingtransition metallic nitride or carbide compound material, for example,tantalum nitride (TaN), titanium nitride (TiN), tantalum carbide (TaC),titanium carbide (TiC), titanium aluminum carbide (TiAlC), andcombinations thereof.

In one or more embodiments, a dummy gate layer 210 can be formed on thework function layer 200, where the dummy gate layer 210 can be formed bya conformal deposition, (e.g., ALD, PEALD, LPCVD). In variousembodiments, dummy gate layer 210 can be amorphous silicon (a-Si).

FIG. 5 is a cross-sectional side view showing a heat treatment of thevertical fins, multilayer fin templates, gate dielectric layer, bottomspacer layer, first work function layer formed, and dummy gate layer, inaccordance with an embodiment of the present invention.

In one or more embodiments, the vertical fins, multilayer fin templates,gate dielectric layer, bottom spacer layer, first work function layerformed, and dummy gate layer can undergo a heat treatment to anneal theformed features and layers.

In various embodiments, the heat treatment can be an anneal at atemperature in a range of about 800° C. to about 1100° C., where thethermal budget can be minimized by conducting the anneal for a durationof about 1 millisecond (msec) to about 10 seconds (sec). In variousembodiments, a flash anneal, rapid thermal anneal, spike anneal, laseranneal, or any suitable combination of these techniques can be used forthe heat treatment.

In one or more embodiments, a lower extension region 134 can be formedin a lower portion of the vertical fins 131, where the lower extensionregion 134 can be formed by the heat treatment to diffuse dopants fromthe bottom source/drain layer 120 into the adjoining vertical fins 131.The lower extension region 134 can be adjacent to the bottom spacerlayer 180, and may extend above the top surface of the bottom spacerlayer to overlap a gate structure.

FIG. 6 is a cross-sectional side view showing a portion of the dummygate layer and work function layer removed from a surfaces of the gatedielectric layer, in accordance with an embodiment of the presentinvention.

In one or more embodiments, a portion of the dummy gate layer 210 andwork function layer 200 removed from a surfaces of the gate dielectriclayer, where the dummy gate layer 210 and work function layer 200 can beremoved using a sequence of selective directional etches (e.g., RIE).Removal of the portions of the dummy gate layer 210 and work functionlayer 200 can expose the underlying gate dielectric layer on the secondfin template slab 161 and on the bottom spacer layer 180 betweenadjacent vertical fins 131.

FIG. 7 is a cross-sectional side view showing a fill layer formed in thespaces between the dummy gate layers on adjacent vertical fins, inaccordance with an embodiment of the present invention.

In one or more embodiments, a fill layer 220 can be formed in the spacesbetween the dummy gate layers 210 on adjacent vertical fins 131, wherethe fill layer 220 can be formed by a blanket deposition (e.g., CVD,PECVD) or spun-on. The fill layer 220 can extend above the dummy gatelayer 210 and gate dielectric layer 190.

In various embodiments the fill layer 220 can be can be a dielectricmaterial, including, but not limited to, silicon oxide (SiO) or a low-kmaterial. A low-k dielectric material can include, but not be limitedto, carbon doped silicon oxide (SiO:C), fluorine doped silicon oxide(SiO:F), silicon carbide (SiC), silicon oxynitride (SiON),silicon-carbon-nitride (SiCN), boron nitride (BN), silicon boron nitride(SiBN), silicon boron carbonitride (SiBCN), silicon oxycabonitride(SiOCN), a polymeric material, for example, tetraethyl orthosilicate(TEOS), hydrogen silsesquioxane (HSQ), methylsilsesquioxane (MSQ), andcombinations thereof.

FIG. 8 is a cross-sectional side view showing a portion of the filllayer and gate dielectric layer removed to expose the underlying secondfin template slab, and the second fin template slab removed to exposethe first fin template slab, in accordance with an embodiment of thepresent invention.

In one or more embodiments, a portion of the fill layer 220 and gatedielectric layer 190 can be removed to expose the underlying second fintemplate slab 161, and the second fin template slab 161 removed toexpose the first fin template slab 151. The portion of the fill layer220 and gate dielectric layer 190 can be removed using achemical-mechanical polishing (CMP). The second fin template slab 161can be removed using a selective isotropic etch (e.g., wet chemical etchor dry plasma etch) and/or a selective directional etch (e.g., RIE).

FIG. 9 is a cross-sectional side view showing a portion of the dummygate layer removed to expose the sidewalls of the work function layer,and the first fin template slab removed to expose the underlying finliner plate, in accordance with an embodiment of the present invention.

In one or more embodiments, a portion of the dummy gate layer 210 can beremoved to expose the sidewalls of the work function layer 200, wherethe portion of the dummy gate layer 210 can be removed using a selectiveisotropic etch and/or a selective directional etch.

In one or more embodiments, the first fin template slab 151 can beremoved to expose the underlying fin liner plate 141, where the firstfin template slab 151 can be removed using a selective isotropic etchand/or a selective directional etch.

FIG. 10 is a cross-sectional side view showing a portion of the workfunction layer and gate dielectric layer removed to expose the sidewallsof the vertical fins and fin liner plate, in accordance with anembodiment of the present invention.

In one or more embodiments, the exposed portion of the work functionlayer 200 can be removed using a selective isotropic etch to expose theunderlying portion of the gate dielectric layer 190. In variousembodiments, the exposed portion of the gate dielectric layer 190 can beremoved using a selective isotropic etch to expose an upper portion ofthe sidewalls of the vertical fins 131.

FIG. 11 is a cross-sectional side view showing a sidewall spacer layerformed on the exposed surfaces of the fill layer, dummy gate layer, workfunction layer, gate dielectric layer, vertical fins, and fin linerplates, in accordance with an embodiment of the present invention.

In one or more embodiments, a sidewall spacer layer 230 can be formed onthe exposed surfaces of the fill layer 220, dummy gate layer 210, workfunction layer 200, gate dielectric layer 190, vertical fins 131, andfin liner plates 141. The sidewall spacer layer 230 can be formed usinga conformal deposition, (e.g., ALD, PEALD), to fill in the space betweenthe sidewalls of the vertical fins 131 and the adjacent fill layer 220.The sidewall spacer layer 230 can be deposited to a thickness thatpinches of the space between the sidewalls of the vertical fins 131 andthe adjacent fill layer 220 and covers the fin liner plates 141 and filllayer 220. The thickness of the sidewall spacer layer 230 can beincreased to greater than half the distance between the sidewalls of thevertical fins 131 and the adjacent fill layer 220, so the sidewallspacer layer 230 has the same thickness on all of the exposed surfacesto control the remaining thicknesses after subsequent etch-backprocesses.

In various embodiments, the sidewall spacer layer 230 can have athickness in a range of about 3 nanometers (nm) to about 8 nm, or about4 nm to about 6 nm, although other widths are also contemplated.

In various embodiments, the sidewall spacer layer 230 can be a hardmaskmaterial, including, but not limited to, silicon nitride (SiN), siliconoxynitride (SiON), silicon carbonitride (SiCN), silicon boronitride(SiBN), silicon borocarbide (SiBC), silicon boro carbonitride (SiBCN),or combinations thereof, where the sidewall spacer layer 230 can be ahardmask material different from the fill layer 220 and gate dielectriclayer 190 to provide etch selectivity.

FIG. 12 is a cross-sectional side view showing a masking layer formed ona portion of the sidewall spacer layer, and an exposed portion of thesidewall spacer layer removed from the fill layer to form sidewallspacers between the vertical fins and fill layer, and the exposed finliner plates removed from the top surfaces of the vertical fins, inaccordance with an embodiment of the present invention.

In one or more embodiments, a masking layer 240 can be formed on aportion of the sidewall spacer layer 230, where the masking layer 240can be an organic planarization layer (OPL). The masking layer 240 canbe patterned and etched to expose a portion of the sidewall spacer layer230 over one or more of the vertical fins 131.

In one or more embodiments, exposed portion of the sidewall spacer layer230 can be removed from the fill layer 220 and from the fin liner plates141 on the vertical fins 131 to form sidewall spacers 235 between thevertical fins 131 and fill layer 220. The exposed portion of thesidewall spacer layer 230 can be removed using a selective, directionaletch (e.g., RIE).

In one or more embodiments, the exposed fin liner plates 141 removedfrom the top surfaces of the vertical fins 131 using a selectiveisotropic etch and/or selective directional etch.

FIG. 13 is a cross-sectional side view showing a top source/drain formedwithin the sidewall spacers on the exposed top surfaces of the verticalfins, in accordance with an embodiment of the present invention.

In one or more embodiments, a first top source/drain 250 can be formedwithin the sidewall spacers 235 on the exposed top surfaces of thevertical fins 131, where the first top source/drain 250 can be formed byan epitaxial or heteroepitaxial growth process. The first topsource/drain 250 can be an n-doped or p-doped semiconductor material,where the dopant type of the first top source/drain 250 can match thedopant type of the bottom source/drain layer 120. The semiconductormaterial can be the same as or different from the semiconductor materialof the vertical fins 131 and/or the bottom source/drain layer 120. Invarious embodiments, the first top source/drain 250 can be asemiconductor material, including, but not limited to n-type (e.g., P orAs) doped silicon (Si) or p-type (e.g., B) doped silicon-germanium(SiGe).

FIG. 14 is a cross-sectional side view showing a protective layer formedon the sidewall spacer layer after removing a masking layer, and on theexposed surfaces of the fill layer, sidewall spacers, and topsource/drains, in accordance with an embodiment of the presentinvention.

In one or more embodiments, the masking layer 240 can be removed fromthe remaining portion of the sidewall spacer layer 230, where themasking layer 240 can be removed, for example, by ashing or a chemicaletch.

In one or more embodiments, a protective layer 260 can be formed on theremaining portions of the sidewall spacer layer 230 and the exposedsurfaces of the fill layer 220, sidewall spacers 235, and topsource/drains 250 after removing the masking layer 240. The protectivelayer 260 can be formed using a conformal or blanket deposition.

In various embodiments, the protective layer 260 can be a hardmaskmaterial. The protective layer 260 can protect the top source/drains 250during subsequent processing.

FIG. 15 is a cross-sectional side view showing a second masking layerformed on a portion of the protective layer, in accordance with anembodiment of the present invention.

In one or more embodiments, a second masking layer 270 formed on aportion of the protective layer 260, where the second masking layer 270can be an OPL material that is patterned and etched to expose theprotective layer 260 over a second subset of vertical fins. In variousembodiments, the exposed portion of the protective layer 260 can beremoved using a selective isotropic or directional etch to expose theunderlying sidewall spacer layer 230.

FIG. 16 is a cross-sectional side view showing a top source/drain formedwithin the sidewall spacers on the exposed top surfaces of the verticalfins after forming sidewall spacers, in accordance with an embodiment ofthe present invention.

In one or more embodiments, exposed portion of the sidewall spacer layer230 can be removed from the fill layer 220 and from the fin liner plates141 on the vertical fins 131 to form sidewall spacers 235 between thevertical fins 131 and fill layer 220. The exposed portion of thesidewall spacer layer 230 can be removed using a selective, directionaletch (e.g., RIE).

In one or more embodiments, the exposed fin liner plates 141 removedfrom the top surfaces of the vertical fins 131 using a selectiveisotropic etch and/or selective directional etch.

In one or more embodiments, a second top source/drain 280 can be formedwithin the sidewall spacers 235 on the exposed top surfaces of thevertical fins 131, where the second top source/drain 280 can be formedby an epitaxial or heteroepitaxial growth process. The second topsource/drain 280 can be an n-doped or p-doped semiconductor material,where the dopant type of the second top source/drain 280 can be theopposite type of doping from the first top source/drains 250 and/or canmatch the dopant type of the bottom source/drain layer 120. Thesemiconductor material can be the same as or different from thesemiconductor material of the vertical fins 131 and/or the bottomsource/drain layer 120. In various embodiments, the second topsource/drain 280 can be a semiconductor material, including, but notlimited to n-type (e.g., P or As) doped silicon (Si) or p-type (e.g., B)doped silicon-germanium (SiGe).

FIG. 17 is a cross-sectional side view showing the second masking layerand protective layer removed, and source/drain caps formed on the topsource/drains, in accordance with an embodiment of the presentinvention.

In one or more embodiments, the second masking layer 270 and portion ofthe protective layer 260 can be removed. In various embodiments, onlythe second masking layer 270 may be removed. The portion of theprotective layer 260 can remain on the top surfaces.

In one or more embodiments, source/drain caps 290 can be formed on thefirst top source/drains 250 and second top source/drain 280 by recessingthe first top source/drains 250 and second top source/drain 280 using aselective etch, and blanket depositing a layer of source/drain capmaterial. A CMP can be used to remove portions of the source/drain capmaterial that extends above the top surface of the fill layer 220.

FIG. 18 is a cross-sectional side view showing the dummy gate layer andwork function layer removed from around a subset of vertical fins, inaccordance with an embodiment of the present invention.

In one or more embodiments, the dummy gate layer 210 can be removed fromaround the first subset of vertical fins 131, to form void spaces 215.In various embodiments, the dummy gate layer 210 can be removed byforming a trench spaced apart from the vertical fin (e.g., in adirection into or out of the figure) and using a selective isotropicetch (e.g., wet chemical etch) to dissolve the dummy gate layer 210.Removing the dummy gate layer 210 can expose work function layer 200.

In one or more embodiments, the work function layer 200 can be removedusing a selective isotropic etch (e.g., wet chemical etch) from withinthe void space 215, where the gate dielectric layer 190 can be exposedby removing the work function layer 200. The dummy gate layer 210 andwork function layer 200 can remain around the second subset of verticalfins 131.

FIG. 19 is a cross-sectional side view showing a replacement workfunction material formed in the spaces formed by removing the dummy gatelayer from around the subset of vertical fins, in accordance with anembodiment of the present invention.

In one or more embodiments, a first replacement work function material300 can be formed in the void space 215 and on the gate dielectric layer190. In various embodiments, the replacement work function material 300can be selected for forming an n-type VT FinFET or a p-type VT FinFET.The replacement work function material 300 can be a conductingtransition metallic nitride or carbide compound material, for example,tantalum nitride (TaN), titanium nitride (TiN), tantalum carbide (TaC),titanium carbide (TiC), titanium aluminum carbide (TiAlC), andcombinations thereof.

FIG. 20 is a cross-sectional side view showing a conductive gate fillformed in the spaces formed by removing the dummy gate layer from arounda second subset of vertical fins, and source/drain and gate contactsformed in an interlayer dielectric (ILD) layer, in accordance with anembodiment of the present invention.

In one or more embodiments, the dummy gate layer 210 and work functionlayer 200 can be removed from around the second subset of vertical fins131 using a spaced-apart trench and an isotropic etch, to form voidspaces. In various embodiments, the work function layer 200 may be lefton the gate dielectric layer 190.

In one or more embodiments, a second replacement work function material310 can be formed in the void space 215 and on the gate dielectric layer190 or the work function layer 200 if the work function layer 200remains. In various embodiments, the second replacement work functionmaterial 310 can be selected for forming an n-type VT FinFET or a p-typeVT FinFET. The second replacement work function material 310 can be aconducting transition metallic nitride or carbide compound material, forexample, tantalum nitride (TaN), titanium nitride (TiN), tantalumcarbide (TaC), titanium carbide (TiC), titanium aluminum carbide(TiAlC), and combinations thereof. The second replacement work functionmaterial 310 can be a different work function material from the firstreplacement work function material 300, so both an n-type VT FinFET anda p-type VT FinFET can be formed on adjacent portions of the substrate110.

In one or more embodiments, portions of the first replacement workfunction material 300 and second replacement work function material 310can be removed from the top surfaces of the fill layer 220, sidewallspacers 235, and source/drain caps 290.

In one or more embodiments, portions of the fill layer 220 can beremoved to form open spaces adjoining the first replacement workfunction material 300 and/or second replacement work function material310, where the fill layer 220 can be removed using lithographicprocesses and a selective isotropic and/or selective directional etch.

In one or more embodiments, a conductive gate fill 320 can be formed inthe open spaces form by removing the fill layer 220, where theconductive gate fill 320 can be formed by a conformal deposition (e.g.,ALD, PEALD).

In various embodiments, the conductive gate fill 320 can be a metal(e.g., tungsten (W), titanium (Ti), tantalum (Ta), ruthenium (Ru),hafnium (Hf), zirconium (Zr), cobalt (Co), nickel (Ni), copper (Cu),aluminum (Al), platinum (Pt), tin (Sn), silver (Ag), gold (Au), aconducting metallic compound material (e.g., tantalum nitride (TaN),titanium nitride (TiN), tantalum carbide (TaC), titanium carbide (TiC),titanium aluminum carbide (TiAlC), tungsten silicide (WSi), tungstennitride (WN), ruthenium oxide (RuO₂), cobalt silicide (CoSi), nickelsilicide (NiSi)), transition metal aluminides (e.g. Ti₃Al, ZrAl), TaC,TaMgC, or any suitable combination of these materials.

In one or more embodiments, the source/drain caps 290 can be replacedwith a silicide contact 330 for forming electrical connections betweenthe top source/drains 250, 280 and source/drain electrical connections340. The source/drain electrical connections 340 in an interlayerdielectric (ILD) layer 350. Gate electrical connections 360 can also beformed in the ILD layer 350 to the conductive gate fill 320.

In one or more embodiments, a second protective layer 370 can be formedon the remaining portion of the first protective layer 260 and on theexposed top surfaces of the sidewalls spacers 235 and remaining filllayer 220. The second protective layer 370 can be a dielectric material,for example, aluminum oxide (AlO), hafnium oxide (HfO), silicon nitride(SiN), and combinations thereof. Openings can be formed through theprotective layers 260, 370 and interlayer dielectric (ILD) layer 350 forremoving the portions of the fill layer 220.

The present embodiments can include a design for an integrated circuitchip, which can be created in a graphical computer programming language,and stored in a computer storage medium (such as a disk, tape, physicalhard drive, or virtual hard drive such as in a storage access network).If the designer does not fabricate chips or the photolithographic masksused to fabricate chips, the designer can transmit the resulting designby physical means (e.g., by providing a copy of the storage mediumstoring the design) or electronically (e.g., through the Internet) tosuch entities, directly or indirectly. The stored design is thenconverted into the appropriate format (e.g., GDSII) for the fabricationof photolithographic masks, which typically include multiple copies ofthe chip design in question that are to be formed on a wafer. Thephotolithographic masks are utilized to define areas of the wafer(and/or the layers thereon) to be etched or otherwise processed.

Methods as described herein can be used in the fabrication of integratedcircuit chips. The resulting integrated circuit chips can be distributedby the fabricator in raw wafer form (that is, as a single wafer that hasmultiple unpackaged chips), as a bare die, or in a packaged form. In thelatter case, the chip is mounted in a single chip package (such as aplastic carrier, with leads that are affixed to a motherboard or otherhigher level carrier) or in a multichip package (such as a ceramiccarrier that has either or both surface interconnections or buriedinterconnections). In any case, the chip is then integrated with otherchips, discrete circuit elements, and/or other signal processing devicesas part of either (a) an intermediate product, such as a motherboard, or(b) an end product. The end product can be any product that includesintegrated circuit chips, ranging from toys and other low-endapplications to advanced computer products having a display, a keyboardor other input device, and a central processor.

It should also be understood that material compounds will be describedin terms of listed elements, e.g., SiGe. These compounds includedifferent proportions of the elements within the compound, e.g., SiGeincludes Si_(x)Ge_(1-x) where x is less than or equal to 1, etc. Inaddition, other elements can be included in the compound and stillfunction in accordance with the present principles. The compounds withadditional elements will be referred to herein as alloys.

Reference in the specification to “one embodiment” or “an embodiment”,as well as other variations thereof, means that a particular feature,structure, characteristic, and so forth described in connection with theembodiment is included in at least one embodiment. Thus, the appearancesof the phrase “in one embodiment” or “in an embodiment”, as well anyother variations, appearing in various places throughout thespecification are not necessarily all referring to the same embodiment.

It is to be appreciated that the use of any of the following “/”,“and/or”, and “at least one of”, for example, in the cases of “A/B”, “Aand/or B” and “at least one of A and B”, is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of both options (A andB). As a further example, in the cases of “A, B, and/or C” and “at leastone of A, B, and C”, such phrasing is intended to encompass theselection of the first listed option (A) only, or the selection of thesecond listed option (B) only, or the selection of the third listedoption (C) only, or the selection of the first and the second listedoptions (A and B) only, or the selection of the first and third listedoptions (A and C) only, or the selection of the second and third listedoptions (B and C) only, or the selection of all three options (A and Band C). This can be extended, as readily apparent by one of ordinaryskill in this and related arts, for as many items listed.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular form “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” and the like, can be used herein for ease of description todescribe one element's or feature's relationship to another elements) orfeatures) as illustrated in the FIGS. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the FIGS. For example, if the device in theFIGS. is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device can be otherwise oriented (rotated 90degrees or at other orientations), and the spatially relativedescriptors used herein can be interpreted accordingly. In addition, itwill also be understood at yen a layer is referred to as being “between”two layers, it can be the only layer between the two layers, or one ormore intervening layers can also be present.

It will be understood that, although the terms first, second, etc. canbe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element discussed belowcould be termed a second element without departing from the scope of thepresent concept.

It will also be understood that when an element such as a layer, regionor substrate is referred to as being “on” or “over” another element, itcan be directly on the other element or intervening elements can also bepresent. In contrast, when an element is referred to as being “directlyon” or “directly over” another element, there are no interveningelements present. It will also be understood that when an element isreferred to as being “connected” or “coupled” to another element, it canbe directly connected or coupled to the other element or interveningelements can be present. In contrast, when an element is referred to asbeing “directly connected” or “directly coupled” to another element,there are no intervening elements present.

Having described preferred embodiments of a device and method offabricating a device (which are intended to be illustrative and notlimiting), it is noted that modifications and variations can be made bypersons skilled in the art in light of the above teachings. It istherefore to be understood that changes may be made in the particularembodiments disclosed which are within the scope of the invention asoutlined by the appended claims. Having thus described aspects of theinvention, with the details and particularity required by the patentlaws, what is claimed and desired protected by Letters Patent is setforth in the appended claims.

What is claimed is:
 1. A fin field effect transistor complementary metaloxide semiconductor (CMOS) device, comprising: a bottom source/drainlayer on a substrate; a plurality of vertical fins in a first subset anda plurality of vertical fins in a second subset on the bottomsource/drain layer; a gate dielectric layer on each of the plurality ofvertical fins in the first subset and each of the plurality of verticalfins in the second subset; a first replacement work function material onthe gate dielectric layer on the plurality of vertical fins in the firstsubset; a second replacement work function layer on the gate dielectriclayer on the plurality of vertical fins in the second subset, whereinthe second replacement work function layer is a different work functionmaterial from the first replacement work function material; a sidewallspacer on the first replacement work function material and gatedielectric layer on the plurality of vertical fins in the first subset;an n-doped top source/drain on each of the plurality of vertical fins inthe first subset; and a p-doped top source/drain on each of theplurality of vertical fins in the second subset.
 2. The CMOS device ofclaim 1, wherein the sidewall spacer is between a fill layer and anupper portion of the vertical fin and between the fill layer and then-doped top source/drain.
 3. The CMOS device of claim 2, furthercomprising a first protective layer on the n-doped top source/drain oneach of the plurality of vertical fins in the first subset, and a secondprotective layer on the p-doped top source/drain on each of theplurality of vertical fins in the second subset.
 4. The CMOS device ofclaim 3, further comprising a conductive gate fill electrically coupledto the first replacement work function material.
 5. The CMOS device ofclaim 4, further comprising a work function layer between the gatedielectric layer and the second replacement work function material onthe plurality of vertical fins in the second subset.
 6. The CMOS deviceof claim 5, wherein the second replacement work function material is adifferent work function material from the first replacement workfunction material.
 7. The CMOS device of claim 6, wherein the firstreplacement work function material is a conducting transition metallicnitride or carbide compound material selected from the group consistingof tantalum nitride (TaN), titanium nitride (TiN), tantalum carbide(TaC), titanium carbide (TiC), titanium aluminum carbide (TiAlC), andcombinations thereof.
 8. The CMOS device of claim 7, wherein the secondreplacement work function material is a conducting transition metallicnitride or carbide compound material selected from the group consistingof tantalum nitride (TaN), titanium nitride (TiN), tantalum carbide(TaC), titanium carbide (TiC), titanium aluminum carbide (TiAlC), andcombinations thereof.
 9. The CMOS device of claim 8, further comprisingan isolation region through the bottom source/drain layer and in thesubstrate that electrically separates the bottom source/drain layer intodifferent segments between the first subset of vertical fins and thesecond subset of vertical fins.
 10. A fin field effect transistorcomplementary metal oxide semiconductor (CMOS) device, comprising: abottom source/drain layer on a substrate; a plurality of vertical finsin a first subset and a plurality of vertical fins in a second subset onthe bottom source/drain layer; an isolation region through the bottomsource/drain layer and in the substrate that electrically separates thebottom source/drain layer into different segments below the plurality ofvertical fins in the first subset and the plurality of vertical fins inthe second subset; a gate dielectric layer on each of the plurality ofvertical fins in the first subset and each of the plurality of verticalfins in the second subset; a work function layer on the gate dielectriclayer on the plurality of vertical fins in the second subset; a firstreplacement work function material on the gate dielectric layer on theplurality of vertical fins in the first subset; a second replacementwork function material on the gate dielectric layer on the plurality ofvertical fins in the second subset, wherein the second replacement workfunction material is a different work function material from the firstreplacement work function material; and an n-doped top source/drain oneach of the plurality of vertical fins in the first subset; and ap-doped top source/drain on each of the plurality of vertical fins inthe second subset.
 11. The CMOS device of claim 10, wherein thematerials forming the plurality of vertical fins and gate dielectriclayer are annealed materials.
 12. The CMOS device of claim 10, whereinthe work function layer is a conducting transition metallic nitride orcarbide compound material selected from the group consisting of tantalumnitride (TaN), titanium nitride (TiN), tantalum carbide (TaC), titaniumcarbide (TiC), titanium aluminum carbide (TiAlC), and combinationsthereof.
 13. The CMOS device of claim 12, wherein the work functionlayer is between the second replacement work function material and thegate dielectric layer.
 14. The CMOS device of claim 13, furthercomprising a sidewall spacer layer on the gate dielectric layer, workfunction layer, and second replacement work function material.
 15. TheCMOS device of claim 14, further comprising a conductive gate fill indirect contact with the sidewall spacer layer, the second replacementwork function material, and the gate dielectric layer, wherein the gatedielectric layer is vertically between the conductive gate fill and theisolation region.
 16. A fin field effect transistor complementary metaloxide semiconductor (CMOS) device, comprising: a bottom source/drainlayer on a substrate; a plurality of vertical fins in a first subset anda plurality of vertical fins in a second subset on the bottomsource/drain layer; a gate dielectric layer on each of the plurality ofvertical fins in the first subset and the plurality of vertical fins inthe second subset; a work function layer on the gate dielectric layer onthe plurality of vertical fins in the second subset; a replacement workfunction material on the gate dielectric layer on the plurality ofvertical fins in the first subset, wherein the replacement work functionmaterial is a different work function material from the work functionlayer; and a sidewall spacer on the replacement work function materialand gate dielectric layer.
 17. The CMOS device of claim 16, furthercomprising a sidewall spacer on the work function layer and gatedielectric layer.
 18. The CMOS device of claim 17, wherein the sidewallsspacers have the same thickness as the combined thickness of thereplacement work function material and the gate dielectric layer. 19.The CMOS device of claim 18, wherein the sidewall spacer layer issilicon nitride (SiN).
 20. The CMOS device of claim 19, furthercomprising a conductive gate fill in physical and electrical contactwith both the replacement work function material and the work functionlayer.